Darren Rowse's Problogger is an informative and useful blog about being a professional blogger.

Darren recently wrote a post on how to get fast traffic to a blog that was painfully clear about a few very important points:
Blogs need to meet a need or solve a problem that potential readers have. The need might seem frivilous (the need to be entertained for example) or it could be a need for information, community, news etc.
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Meet a need and you give people a reason to subscribe to your blog and to pass it on to others. Create a blog that doesn’t really prove useful in any way and you’re unlikely to build a successful blog.
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If you’re expecting big traffic quickly you’re asking the wrong guy. My strategy has always been to write content that people will want to read now - but also for years to come. Some call this ‘evergreen’ content and it takes time to write. It might not bring traffic quickly but if you write something that is still relevant in a year or more you’ll continue to draw traffic to it.
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... to be honest there’s a lot of bloggers looking for quick traffic and quick money and a lot of people promising to teach them how to get it - but that’s not my experience of blogging.
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Take a long term view, build something that matters and you’ll build a blog that grows in traffic over the long haul.
"Build something that matters" -- I like that!